Flavan derivatives. XX. A new glycoside and other extractives from <i>Acacia ixiophylla</i> : Rhamnitrin (rhamnetin 3α-L-rhamnoside)

Abstract

Rhamnitrin, a new glycoside from the shrub Acacia ixiophylla , is shown to be quercetin 7-methyl ether 3a-L-rhamnoside. A quercetin diglucoside (considered to be the 3,3'-diglucoside), quercitrin, queroetin, rhamnetin, apigenin, apigenin 7,4'-dimethyl ether, and (-)-epicatechin were also isolated. The extractive consisted mainly of mixtures of condensed tannins derived from 5,7,3',4'-tetrahydroxy-flavan-3-o1 and -3,4-diol monomers, and the lower polymers appear to be responsible for the antitumour activity of the extractive.